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Abstract:

A touch screen sensor includes a visible light transparent substrate and
an electrically conductive micropattern disposed on or in the visible
light transparent substrate. The micropattern includes a first region
micropattern within a touch sensing area and a second region
micropattern. The first region micropattern has a first sheet resistance
value in a first direction, is visible light transparent, and has at
least 90% open area. The second region micropattern has a second sheet
resistance value in the first direction. The first sheet resistance value
is different from the second sheet resistance value.

Claims:

1. A touch screen sensor, comprising: a visible light transparent
substrate; an electrically conductive micropattern disposed on or in the
visible light transparent substrate, the micropattern having: a conductor
trace width of about X+0.5 in units of micrometers; and an open area
fraction between about [95-X]% and 99.5%, wherein 0.ltoreq.X≦4.5.

7. The touch screen sensor of claim 1, wherein the conductor trace has a
thickness of less than about 500 nanometers.

8. A touch screen sensor element, comprising: a first patterned substrate
comprising a first patterned metalized film having a plurality of first
continuous regions alternating between a plurality of first discontinuous
regions, each of the first continuous regions having a plurality of first
traces forming a first mesh structure; a second patterned substrate
comprising a second patterned metalized film having a plurality of second
continuous regions alternating between a plurality of second
discontinuous regions, each of the second continuous regions having a
plurality of second traces forming a second mesh structure, wherein the
first and second patterned substrates are adhered together; the first
traces and the second traces have a width between about 0.5 and 5
micrometers; and the first mesh structure and the second mesh structure
each have an open area between 90 and 99.5%.

9. The touch screen sensor element of claim 8, wherein the first traces
and the second traces each have a width of about X+0.5 in units of
micrometers; and the first mesh structure and the second mesh structure
each have an open area between about [95-X]% and 99.5%, wherein
0.ltoreq.X≦4.5.

10. The touch sensor element of claim 8, wherein the first traces and the
second traces each have width between 0.5 and 3 micrometers and the first
mesh structure and the second mesh structure each an open area between
96% and 99.5%.

11. The touch sensor element of claim 8, wherein the first continuous
regions and the second continuous regions each have sheet resistance
within the range of 1 to 500 ohms per square.

12. The touch sensor element of claim 8, wherein the first continuous
regions and the second continuous regions each have sheet resistance
within the range of 5 to 100 ohms per square.

13. The touch sensor element of claim 8, wherein the first continuous
regions and the second continuous regions each have sheet resistance
within the range of 5 to 40 ohms per square.

14. The touch sensor element of claim 8, wherein the first and second
patterned metalized film comprises gold, silver, palladium, platinum,
aluminum, copper, nickel, tin, or alloys or combinations thereof.

15. The touch screen sensor element of claim 8, further connected to a
touch sensor drive device comprising integrated circuits used to make
mutual capacitance measurement of the sensor element.

16. A touch screen sensor element, comprising: a first patterned
substrate comprising a first patterned metalized film having a plurality
of first continuous regions alternating between a plurality of first
discontinuous regions, each of the first continuous regions having a
plurality of first traces forming a first mesh structure; a second
patterned substrate comprising a second patterned metalized film having a
plurality of second continuous regions alternating between a plurality of
second discontinuous regions, each of the second continuous regions
having a plurality of second traces forming a second mesh structure,
wherein the first and second patterned substrates are adhered together;
the first traces and the second traces have a width between about 0.5 and
5 micrometers; and the first mesh structure and the second mesh structure
each have an open area between 95 and 99.95%.

17. A touch screen sensor, comprising: a visible light transparent
substrate; an electrically conductive pattern disposed on or in the
visible light transparent substrate, the pattern including: a visible
light transparent micropattern region comprising a plurality of traces
forming a mesh structure; and a region having a larger feature that is
not transparent, wherein the traces have a width between 0.5 and 5
micrometers; the mesh structure has an open area between 95 and 99.95%;
and the visible light transparent micropattern region and the region
having the larger feature include the same metal at approximately the
same thickness.

18. The touch screen sensor of claim 17, wherein the larger feature is a
conductive trace that makes contact to the visible light transparent
micropattern region.

19. The touch screen sensor of claim 18, wherein the conductive trace
makes contact to a pad making contact with an electronic decoding, signal
generation, or signal processing device.

20. The touch screen sensor of claim 17, wherein the larger feature has a
width between 25 micrometers and 500 micrometers.

21. The touch sensor of claim 20, wherein the larger feature has a width
between 50 micrometers and 100 micrometers.

Description:

[0001] This application is a continuation of U.S. application Ser. No.
12/393,185, now allowed, filed Feb. 26, 2009, the disclosure of which is
incorporated by reference herein in its entirety.

BACKGROUND

[0002] Touch screen sensors detect the location of an object (e.g. a
finger or a stylus) applied to the surface of a touch screen display or
the location of an object positioned near the surface of a touch screen
display. These sensors detect the location of the object along the
surface of the display, e.g. in the plane of a flat rectangular display.
Examples of touch screen sensors include capacitive sensors, resistive
sensors, and projected capacitive sensors. Such sensors include
transparent conductive elements that overlay the display. The elements
are combined with electronic components that use electrical signals to
probe the elements in order to determine the location of an object near
or in contact with the display.

[0003] In the field of touch screen sensors, there is a need to have
improved control over the electrical properties of the transparent touch
screen sensors, without compromising optical quality or properties of the
display. A transparent conductive region of a typical touch screen sensor
includes a continuous coating of a transparent conducting oxide (TCO)
such as indium tin oxide (ITO), the coating exhibiting electrical
potential gradients based on the location or locations of contact to a
voltage source and the overall shape of the region. This fact leads to a
constraint on possible touch sensor designs and sensor performance, and
necessitates such measures as expensive signal processing electronics or
placement of additional electrodes to modify the electrical potential
gradients. Thus, there is a need for transparent conductive elements that
offer control over electrical potential gradients that is independent of
the aforementioned factors.

[0004] There is an additional need in the field of touch screen sensors
that relates to flexibility in the design of electrically conductive
elements. The fabrication of touch screen sensors using patterned
transparent conducting oxides (TCO) such as indium tin oxide (ITO) often
places limitations on conductor design. The limitations relate to a
constraint caused by patterning all of the conductive elements from a
transparent sheet conductor that has a single value of isotropic sheet
resistance.

BRIEF SUMMARY

[0005] In one aspect, the present disclosure relates to touch screen
sensors having a transparent substrate and a micropatterned conductor
(typically metal) of specified pattern geometry to achieve high optical
quality. In general, optical quality can be expressed in terms of visible
light transmittance, haze, and conductor visibility, as determined
observing the conductor as it assembled in the touch screen sensor with
unaided eyes. The geometry of the micropatterned conductor can be defined
with parameters such as, but not limited to, the width of the conductor
traces (sometimes referred to as "lines") used for the micropattern, the
density of the lines, and the uniformity of the density of the lines. In
a first embodiment for a touch screen sensor having good optical quality,
the touch screen sensor, comprises a visible light transparent substrate;
and an electrically conductive micropattern disposed on or in the visible
light transparent substrate. The micropattern has a conductor trace width
of about [X+0.5] in units of micrometers; and an open area fraction
between about [95-X]% and 99.5%, where 0≦X≦4.5. In another
embodiment, the touch screen sensor of has an open area fraction between
about [98.5-(2.5/3.5)]% and [99.5-(X/3.5)]% wherein
0≦X≦3.5. In another embodiment, the touch screen sensor has
a haze value of less than 10%, preferably less than 5%, and visible light
transmittance greater than 75%, preferably greater than 85%. In another
embodiment, the conductor trace width of the touch screen sensor is less
than about 6 micrometer and having a pitch of less than about 300
micrometer. In another embodiment, the conductor trace of the touch
screen sensor has a thickness of less than about 500 nanometers. In
another embodiment, the pitch is about 1 mm to 4 mm, with a conductor
width less between 3 and 10 microns.

[0007] In a first embodiment for a touch screen sensors having varying
sheet resistance, the sensor includes a visible light transparent
substrate and an electrically conductive micropattern disposed on or in
the visible light transparent substrate. The micropattern includes a
first region micropattern within a touch sensing area and a second region
micropattern. The first region micropattern has a first sheet resistance
value in a first direction, is visible light transparent, and has at
least 90% open area. The second region micropattern has a second sheet
resistance value in the first direction. The first sheet resistance value
is different from the second sheet resistance value.

[0008] In another embodiment for a touch screen sensors having varying
sheet resistance, the sensor includes a visible light transparent
substrate and an electrically conductive micropattern disposed on or in
the visible light transparent substrate. The micropattern includes a
first region micropattern within a touch sensing area, the first region
micropattern having an anisotropic first sheet resistance, being visible
light transparent, and having at least 90% open area.

[0009] In another embodiment for a touch screen sensors having varying
sheet resistance, the sensor includes a visible light transparent
substrate and an electrically conductive micropattern disposed on or in
the visible light transparent substrate. The micropattern includes a
first region micropattern within a touch sensing area and a second region
micropattern. The electrically conductive micropattern has metallic
linear electrically conductive features with a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has a first sheet resistance value in a first direction
between 5 and 500 ohm per square, is visible light transparent, and has
between 95% and 99.5% open area (or in another embodiment even 99.9% open
area, or even 99.95% open area). The second region micropattern has a
second sheet resistance value in the first direction. The first sheet
resistance value is different from the second sheet resistance value.

[0010] In a further embodiment for a touch screen sensors having varying
sheet resistance, the sensor includes a visible light transparent
substrate and an electrically conductive micropattern disposed on or in
the visible light transparent substrate. The micropattern includes a
first region micropattern within a touch sensing area. The electrically
conductive micropattern includes metallic linear electrically conductive
features having a thickness of less than 500 nanometers and a width
between 0.5 and 5 micrometers. The first region micropattern has an
anisotropic first sheet resistance with a difference in sheet resistance
values for orthogonal directions of a factor of at least 1.5, is visible
light transparent, and has between 95% and 99.5% open area.

[0011] In a further embodiment, a touch screen sensor is described, the
touch screen sensor comprising a visible light transparent substrate; and
a touch-sensitive electrically conductive micropattern disposed on or in
the visible light transparent substrate; wherein the micropattern
includes conductive traces with width between about 1 and 10 micrometers.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The invention may be more completely understood in consideration of
the following detailed description of various embodiments of the
invention in connection with the accompanying drawings, in which:

[0022] FIG. 10 illustrates a cross section of an example of a matrix touch
sensor constructed from two layers of the materials from FIG. 9;

[0023] FIG. 11 illustrates the conductor micropattern for one embodiment
of the touch screen sensor;

[0024] FIG. 12 illustrates a portion of the conductor micropattern
illustrated in FIG. 3, the portion including a conductive mesh with
selective breaks for modulating the local sheet resistance as well as a
larger feature in the form of a contact pad;

[0025] FIG. 13 illustrates a modulation in resistance along the horizontal
mesh bars given in FIG. 3, created by selective breaks in the contiguous
mesh;

[0026] FIG. 14 is a circuit diagram that approximates the properties of
the conductor micropattern illustrated in FIG. 3, where capacitive plates
are separated by resistive elements;

[0027] FIG. 15 illustrates the conductor micropattern for one embodiment
of the touch screen sensor, the micropattern including regions labeled
15a-15e with different sheet resistance created in part by selective
breaks in the electrically conductive micropattern mesh;

[0028] FIGS. 15a-15e each illustrate a portion of the varying conductor
micropattern illustrated in FIG. 15;

[0029] FIG. 16 illustrates the distribution of resistance per unit length
along the long axis of the wedge-shaped transparent conductive region
having regions 15a and 15b therein, as compared with the resistance per
unit length for a similarly shaped region comprising only a uniform
transparent conducting oxide, ITO;

[0030] FIG. 17 illustrates the arrangement of layers that are laminated
together to form one embodiment of the touch screen sensor, an X-Y grid
type projected capacitive touch screen sensor;

[0031] FIG. 18 illustrates the conductor micropattern for the X-layer or
the Y-layer of an embodiment of the touch screen sensor according to FIG.
17;

[0032] FIG. 19 illustrates a portion of the conductor micropattern
illustrated in FIG. 10, the portion including a visible light transparent
conductive mesh contacting a larger feature in the form of a contact pad,
as well as electrically isolated conductor deposits in the space between
the mesh regions;

[0033] FIG. 20 illustrates the conductor micropattern for the X-layer or
the Y-layer of another embodiment of the touch screen sensor according to
FIG. 9;

[0034] FIG. 21 illustrates a portion of the conductor micropattern given
in FIG. 12, the portion including a visible light transparent conductive
mesh contacting a larger feature in the form of a contact pad, as well as
electrically isolated conductor deposits in the space between the mesh
regions;

[0035] FIG. 22 illustrates the conductor micropattern for the X-layer or
the Y-layer of another embodiment of the touch screen sensor according to
FIG. 17; and

[0036] FIG. 23 illustrates a portion of the conductor micropattern given
in FIG. 22, the portion including a visible light transparent conductive
mesh contacting a larger feature in the form of a contact pad, as well as
electrically isolated conductor deposits in the space between the mesh
regions.

[0037]FIG. 24 illustrates a graph to reflect optical quality of the touch
screen sensor, the graph being a plot of Percent of Open Area vs.
conductor trace width (in micrometers), with Region 3 being good optical
quality that can be used for a touch screen sensor, Region 2 being better
in optical quality as compared to Region 2, and Region 1 having the best
optical quality of the three regions. Percent of Open Area is used
interchangeably with open area fraction herein.

[0038] FIG. 25 and FIG. 26 illustrate scanning electron photomicrographs
of the geometry for the hexagonal mesh (sometimes referred to as "hex"
mesh) and square mesh that are characteristic of Examples 6 through 40.
The light shade lines in each image represent the pattern of the metal
conductor and the dark area represents the substrate used in the
Examples.

[0039] FIGS. 27, 27a, and 27b illustrate various portions of a first
patterned substrate;

[0040] FIGS. 28, 28a, and 28b illustrate various portions of a second
patterned substrate;

[0041] FIG. 29 illustrates a projected capacitive touch screen transparent
sensor element constructed from the first and second patterned substrates
of FIGS. 27 and 28.

[0042] The figures are not necessarily to scale. Like numbers used in the
figures refer to like components. However, it will be understood that the
use of a number to refer to a component in a given figure is not intended
to limit the component in another figure labeled with the same number.

DETAILED DESCRIPTION

[0043] In the following description, reference is made to the accompanying
set of drawings that form a part hereof and in which are shown by way of
illustration several specific embodiments. It is to be understood that
other embodiments are contemplated and may be made without departing from
the scope or spirit of the present invention. The following detailed
description, therefore, is not to be taken in a limiting sense.

[0044] All scientific and technical terms used herein have meanings
commonly used in the art unless otherwise specified. The definitions
provided herein are to facilitate understanding of certain terms used
frequently herein and are not meant to limit the scope of the present
disclosure.

[0045] Unless otherwise indicated, all numbers expressing feature sizes,
amounts, and physical properties used in the specification and claims are
to be understood as being modified in all instances by the term "about."
Accordingly, unless indicated to the contrary, the numerical parameters
set forth in the foregoing specification and attached claims are
approximations that can vary depending upon the desired properties sought
to be obtained by those skilled in the art utilizing the teachings
disclosed herein.

[0046] The recitation of numerical ranges by endpoints includes all
numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80,
4, and 5) and any range within that range.

[0047] As used in this specification and the appended claims, the singular
forms "a", "an", and "the" encompass embodiments having plural referents,
unless the context clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the context clearly
dictates otherwise.

[0048] As used herein, "visible light transparent" refers to the level of
transmission being at least 60 percent transmissive to at least one
polarization state of visible light, where the percent transmission is
normalized to the intensity of the incident, optionally polarized light.
It is within the meaning of visible light transparent for an article that
transmits at least 60 percent of incident light to include microscopic
features (e.g., dots, squares, or lines with minimum dimension, e.g.
width, between 0.5 and 10 micrometers, or between 1 and 5 micrometers)
that block light locally to less than 80 percent transmission (e.g., 0
percent); however, in such cases, for an approximately equiaxed area
including the microscopic feature and measuring 1000 times the minimum
dimension of the microscopic feature in width, the average transmittance
is greater than 60 percent.

[0049] The present disclosure relates to touch screen sensors with
electrical and optical properties that are engineered through design of
conductor micropatterns comprised therein. There are several advantages
that are created for touch screen sensors by the incorporation of the
conductor micropatterns described herein. In some embodiments, the
transparent conductive properties within a transparent conductive region
are engineered to control the electrical potential gradient within the
touch sensing region during use. This leads to simplicity of signal
processing electronics and, for some touch screen sensor types simplicity
in the design of (or elimination of the need for) additional conductor
patterns that would otherwise be needed for electrical potential gradient
(electrical field) linearization. In some embodiments, the electrical
properties of the touch screen sensors described herein are designed to
generate a controlled electrical potential gradient along a transparent
sensor element. E.g., the electrical properties are designed to create a
linear electrical potential gradient along a particular direction within
a transparent conductive region, the overall shape of which would
ordinarily lead to a non-linear gradient if a standard transparent
conductor material was used (e.g., continuous ITO coating). In some
embodiments, the electrical properties are designed to create a level of
non-linearity of electrical potential gradient for a transparent
conductive region that is greater than that which would be present within
a transparent conductive region of the same shape but comprised of a
standard transparent conductor material (e.g., continuous ITO coating).
In more detail, for a rectangular capacitive touch screen comprising a
contiguous transparent sheet conductor in the form of a micropatterned
conductor with electrical connections made to the corners of the sensing
area, the linearity of electrical potential gradient (and uniformity of
electric field) across the sensing area in the vertical and horizontal
directions can be improved by engineering the area distribution of sheet
resistance values and anisotropy in such a way as to distribute the field
more uniformly. In other embodiments, the sensor includes conductor
elements comprised of the same conductor material at the same thickness
(i.e., height), but with different effective sheet resistance by virtue
of micropatterning. E.g., in some embodiments, the same conductor
material at the same thickness (i.e., height) is used to generate
conductive traces that define a first micropattern geometry, leading to a
first level of sheet resistance in a transparent conductive region, and
conductive traces that define a second micropattern geometry, leading to
a second level of sheet resistance in a second transparent conductive
region. This disclosure also allows for improved efficiency and resource
utilization in the manufacture of transparent display sensors, e.g.
through the avoidance of rare elements such as indium for some
embodiments, e.g. embodiments based on micropatterned metal conductors.

[0050] The disclosure further relates to contact or proximity sensors for
touch input of information or instructions into electronic devices (e.g.,
computers, cellular telephones, etc.) These sensors are visible light
transparent and useful in direct combination with a display, overlaying a
display element, and interfaced with a device that drives the display (as
a "touch screen" sensor). The sensor element has a sheet like form and
includes at least one electrically insulating visible light transparent
substrate layer that supports one or more of the following: i) conductive
material (e.g., metal) that is mesh patterned onto two different regions
of the substrate surface with two different mesh designs so as to
generate two regions with different effective sheet resistance values,
where at least one of the regions is a transparent conductive region that
lies within the touch-sensing area of the sensor; ii) conductive material
(e.g., metal) that is patterned onto the surface of the substrate in a
mesh geometry so as to generate a transparent conductive region that lies
within the touch sensing area of the sensor and that exhibits anisotropic
effective sheet resistance; and/or iii) conductive material (e.g., metal)
that is patterned onto the surface of the substrate in a mesh geometry
within an effectively electrically continuous transparent conductive
region, the geometry varying within the region so as to generate
different values of local effective sheet resistance in at least one
direction (e.g., continuously varying sheet resistance for the
transparent conductive region), where the region lies within the sensing
area of the touch sensor.

[0051] The sensing area of a touch sensor is that region of the sensor
that is intended to overlay, or that overlays, a viewable portion of an
information display and is visible light transparent in order to allow
viewability of the information display. Viewable portion of the
information display refers to that portion of an information display that
has changeable information content, e.g. the portion of a display
"screen" that is occupied by pixels, e.g. the pixels of a liquid crystal
display.

[0052] This disclosure further relates to touch screen sensors that are of
the resistive, capacitive, and projected capacitive types. The visible
light transparent conductor micropatterns are particularly useful for
projected capacitive touch screen sensors that are integrated with
electronic displays. As a component of projected capacitive touch screen
sensors, the visible light transparent conductive micropattern are useful
for enabling high touch sensitivity, multi-touch detection, and stylus
input.

[0053] The two or more different levels of sheet resistance, the
anisotropy of the sheet resistance, or the varying level of sheet
resistance within a transparent conductive region can be controlled by
the geometries of two-dimensional meshes that make up the transparent
micropatterned conductors, as described below.

[0054] While the present invention is not so limited, an appreciation of
various aspects of the invention will be gained through a discussion of
the examples provided below.

[0055] FIG. 1 illustrates a schematic diagram of a touch screen sensor
100. The touch screen sensor 100 includes a touch screen panel 110 having
a touch sensing area 105. The touch sensing area 105 is electrically
coupled to a touch sensor drive device 120. The touch screen panel 110 is
incorporated into a display device.

[0056] FIG. 2 illustrates a perspective view of a conductive visible light
transparent region 101 that would lie within a touch sensing area of a
touch screen panel, e.g., touch sensing area 105 in FIG. 1. The
conductive visible light transparent region 101 includes a visible light
transparent substrate 130 and an electrically conductive micropattern 140
disposed on or in the visible light transparent substrate 130. The
visible light transparent substrate 130 includes a major surface 132 and
is electrically insulating. The visible light transparent substrate 130
can be formed of any useful electrically insulating material such as,
e.g., glass or polymer. Examples of useful polymers for light transparent
substrate 130 include polyethylene terephthalate (PET) and polyethylene
naphthalate (PEN). The electrically conductive micropattern 140 can be
formed of a plurality of linear metallic features.

[0057] FIG. 2 also illustrates an axis system for use in describing the
conductive visible light transparent region 101 that would lie within a
touch sensing area of a touch screen panel. Generally, for display
devices, the x and y axes correspond to the width and length of the
display and the z axis is typically along the thickness (i.e., height)
direction of a display. This convention will be used throughout, unless
otherwise stated. In the axis system of FIG. 2, the x axis and y axis are
defined to be parallel to a major surface 132 of the visible light
transparent substrate 130 and may correspond to width and length
directions of a square or rectangular surface. The z axis is
perpendicular to that major surface and is typically along the thickness
direction of the visible light transparent substrate 130. A width of the
plurality of linear metallic features that form the electrically
conductive micropattern 140 correspond to an x-direction distance for the
parallel linear metallic features that extend linearly along the y axis
and a y-direction distance for the orthogonal linear metallic features
correspond to a width of the orthogonal linear metallic features. A
thickness or height of the linear metallic features corresponds to a
z-direction distance.

[0058] In some embodiments, the conductive visible light transparent
region 101 that would lie within a touch sensing area of a touch screen
panel includes two or more layers of visible light transparent substrate
130 each having a conductive micropattern 140.

[0059] The conductive micropattern 140 is deposited on the major surface
132. Because the sensor is to be interfaced with a display to form a
touch screen display, or touch panel display, the substrate 130 is
visible light transparent and substantially planar. The substrate and the
sensor may be substantially planar and flexible. By visible light
transparent, what is meant is that information (e.g., text, images, or
figures) that is rendered by the display can be viewed through the touch
sensor. The viewability and transparency can be achieved for touch
sensors including conductors in the form of a deposited metal, even metal
that is deposited with thickness great enough to block light, if the
metal is deposited in an appropriate micropattern.

[0060] The conductive micropattern 140 includes at least one visible light
transparent conductive region overlaying a viewable portion of the
display that renders information. By visible light transparent
conductive, what is meant is that the portion of the display can be
viewed through the region of conductive micropattern and that the region
of micropattern is electrically conductive in the plane of the pattern,
or stated differently, along the major surface of the substrate onto
which the conductive micropattern is deposited and to which it is
adjacent. Preferred conductive micropatterns include regions with two
dimensional meshes, e.g. square grids, rectangular (non-square) grids, or
regular hexagonal networks, where conductive traces define enclosed open
areas within the mesh that are not deposited with conductor that is in
electrical contact with the traces of the mesh. The open spaces and
associated conductor traces at their edges are referred to herein as
cells. Other useful geometries for mesh cells include random cell shapes
and irregular polygons.

[0061] In some embodiments, the conductive traces defining the conductive
micropattern are designed not to include segments that are approximately
straight for a distance greater than the combined edge length of five
adjacent cells, preferably four adjacent cells, more preferably three
adjacent cells, even more preferably two adjacent cells. Most preferably,
the traces defining the micropattern are designed not to include segments
that are straight for a distance greater than the edge length of a single
cell. Accordingly, in some embodiments, the traces that define the
micropattern are not straight over long distances, e.g., 10 centimeters,
1 centimeter, or even 1 millimeter. Patterns with minimal lengths of
straight line segments, as just described, are particularly useful for
touch screen sensors with the advantage of causing minimal disturbance of
display viewability.

[0062] The two-dimensional geometry of the conductive micropattern (that
is, geometry of the pattern in the plane or along the major surface of
the substrate) can be designed, with consideration of the optical and
electrical properties of the conductor material, to achieve special
transparent conductive properties that are useful in touch screen
sensors. E.g., whereas a continuous (un-patterned) deposit or coating of
conductor material has a sheet resistance that is calculated as its bulk
resistivity divided by its thickness, in the present invention different
levels of sheet resistance are engineered by micropatterning the
conductor as well.

[0063] In some embodiments, the two-dimensional conductive micropattern is
designed to achieve anisotropic sheet resistance in a conductive region
(e.g., a visible light transparent conductive region) of the sensor. By
anisotropic sheet resistance, what is meant is that the magnitude of the
sheet resistance of the conductive micropattern is different when
measured or modeled along two orthogonal directions.

[0064] In contrast, in some embodiments, the two-dimensional conductive
micropattern is designed to achieve isotropic sheet resistance in a
conductive region (e.g., a visible light transparent conductive region)
of the sensor. By isotropic sheet resistance, what is meant is that the
magnitude of the sheet resistance of the conductive micropattern is the
same when measured or modeled along any two orthogonal directions in the
plane, as in the case for a square grid formed with traces of constant
width for both directions.

[0065] Anisotropic sheet resistance within a region can include sheet
resistance in one direction that is at least 10 percent greater than the
sheet resistance in the orthogonal direction, or at least 25 percent
greater, at least 50 percent greater, at least 100 percent greater, at
least 200 percent greater, at least 500 percent greater, or even at least
10 times greater. In some embodiments, anisotropic sheet resistance
within a region includes sheet resistance in one direction that is
greater than the sheet resistance in the orthogonal direction by a factor
of at least 1.5. In some embodiments, anisotropic sheet resistance within
a region includes sheet resistance in one direction that is greater than
the sheet resistance in the orthogonal direction by a factor between 1.1
and 10, in other embodiments between 1.25 and 5, and in yet other
embodiments between 1.5 and 2.

[0066] An example of a conductive micropattern geometry that can generate
anisotropic sheet resistance is approximately a rectangular microgrid
(non-square) with fixed widths for the conductive traces. For such a
rectangular microgrid (non-square), anisotropic sheet resistance can
result from a repeating geometry for the cells of the grid that includes
one edge that is 10 percent longer than the other, 25 percent longer than
the other, at least 50 percent longer than the other, 100 percent longer
than the other, or even 10 times longer than the other. Anisotropic sheet
resistance can be created by varying the width of traces for different
directions, e.g. in an otherwise highly symmetrical pattern of cells for
a mesh. An example of the latter approach to generating anisotropic sheet
resistance is a square grid of conductive traces, e.g. with pitch of 200
micrometers, wherein the traces in a first direction are 10 micrometers
wide and the traces in the orthogonal direction are 9 micrometers in
width, 7.5 micrometers in width, 5 micrometers in width, or even 1
micrometer in width. Anisotropic sheet resistance within a region can
include a finite, measurable sheet resistance in one direction and
essentially infinite sheet resistance in the other direction, as would be
generated by a pattern of parallel conductive lines. In some embodiments,
as described above, the anisotropic sheet resistance within a region
includes a finite, measurable sheet resistance in a first direction and a
finite, measurable sheet resistance in the direction orthogonal to the
first direction.

[0067] For the purpose of determining whether a region of conductive
micropattern is isotropic or anisotropic, it will be appreciated by those
skilled in the art that the scale of the region of interest must be
reasonably selected, relative to the scale of the micropattern, to make
relevant measurements or calculations of properties. E.g., once a
conductor is patterned at all, it is trivial for one to select a location
and a scale on which to make a measurement that will yield a difference
in sheet resistance for different directions of measurement. The
following detailed example can make the point more clearly. If one
considered a conductor pattern of isotropic geometry in the form of a
square grid with 100 micrometer wide conductor traces and 1 millimeter
pitch (leading to 900 micrometer by 900 micrometer square openings in the
grid), and one made four point probe measurements of sheet resistance
within one of the traces along the edge of a square opening with a probe
having fixed spacing along the four linearly arranged probes of 25
micrometers (leading to a separation between the two current probes, the
outside probes, of 75 micrometers), different levels of sheet resistance
will be calculated by the measured values of current and voltage
depending on whether the probes were aligned parallel to the trace or
orthogonal to the trace. Thus, even though the square grid geometry would
yield isotropic sheet resistance on a scale larger than the square grid
cell size, it is possible for one to carry out measurements of sheet
resistance that would suggest anisotropy. Thus, for the purpose of
defining anisotropy of the sheet resistance of a conductive micropattern
in the current disclosure, e.g. a visible light transparent conductive
region of the micropattern that comprises a mesh, the relevant scale over
which the sheet resistance should be measured or modeled is greater than
the length scale of a cell in the mesh, preferably greater than the
length scale of two cells. In some cases, the sheet resistance is
measured or modeled over the length scale of five or more cells in the
mesh, to show that the mesh is anisotropic in its sheet resistance.

[0068] In contrast to embodiments where the conductive micropattern
exhibits anisotropy of sheet resistance in a region, sensors including
transparent conducting oxide thin films (e.g., indium tin oxide, or ITO)
exhibit isotropic sheet resistance in contiguous regions of the
conductor. In the latter case, one can measure or model that as
four-point probe measurements of sheet resistance of a contiguous region
are made in different directions and with decreasing spacing between the
probes, the same readings of current and voltage for different directions
clearly indicate isotropy.

[0069] In some embodiments, the two-dimensional conductive micropattern is
designed to achieve different levels, or magnitudes, of sheet resistance
in two different patterned conductor regions of the sensor, when measured
in a given direction. E.g., with respect to the different levels of sheet
resistance, the greater of the two may exceed the lesser by a factor
greater than 1.25, a factor greater than 1.5, a factor greater than 2, a
factor greater than 5, a factor greater than 10, or even a factor greater
than 100. In some embodiments, the greater of the two sheet resistance
values exceeds the lesser by a factor between 1.25 and 1000, in other
embodiments between 1.25 and 100, in other embodiments between 1.25 and
10, in other embodiments between 2 and 5. For a region to be regarded as
having a different sheet resistance from that of another region, it would
have a sheet resistance that is greater or lesser than that of the other
region by a factor of at least 1.1.

[0070] In some embodiments, the micropattern is designed to achieve the
aforementioned different levels of sheet resistance for two patterned
conductor regions that are electrically contiguous, which is to say that
they are patterned conductor regions that are in electrical contact with
each other along a boundary between them. Each of the two patterned
conductor regions that share a conductive boundary may have uniform
respective pattern geometries, but again different. In some embodiments,
the micropattern is designed to achieve the different levels of sheet
resistance for two different patterned conductor regions that are
electrically noncontiguous, which is to say that the they are patterned
conductor regions that share no boundary between them for which the
patterned regions are in electrical contact along that boundary. Each of
the two patterned conductor regions that share no conductive boundary
between them may have uniform respective pattern geometries, but again
different. For electrically noncontiguous regions, it is within the scope
of the disclosure for them both to make electrical contact in the pattern
to the same solid conductor element, e.g. a bus bar or pad. In some
embodiments, the micropattern is designed to achieve the different levels
of sheet resistance for two regions that are electrically isolated from
each other and thus can be addressed independently by electrical signals.
Each of the two mesh regions that are electrically isolated may have a
uniform pattern geometry, but again different. Finally, in some
embodiments, the micropattern is designed to achieve different levels of
sheet resistance for two different regions by creating continuously
varying sheet resistance from the first region to the second, and example
of two regions that are electrically contiguous.

[0071] The two dimensional conductive micropatterns that include two
regions with different sheet resistance in a measurement direction are
useful for designing a visible light transparent conductive region in the
sensing area with a preferred level of sheet resistance for that region
(e.g., low sheet resistance between 5 and 100 ohms per square), including
varying or anisotropic sheet resistance optionally, and designing an
electrical element, e.g. a resistor element, as part of the touch screen
sensor that may or may not lie within the sensing area, the resistor
element comprising a sheet conductor with sheet resistance selected
optimally for the resistor function (e.g., higher sheet resistance
between 150 and 1000 ohms per square) and possibly in light of other
design constraints, e.g. the constraint of minimizing the footprint of
the resistor.

[0072] The sheet resistance of the conductive micropattern, in regions and
directions with finite sheet resistance that can be measured or modeled,
as described above, may fall within the range of 0.01 ohms per square to
1 megaohm per square, or within the range of 0.1 to 1000 ohms per square,
or within the range of 1 to 500 ohms per square. In some embodiments, the
sheet resistance of the conductive micropattern falls within the range of
1 to 50 ohms per square. In other embodiments, the sheet resistance of
the conductive micropattern falls within the range of 5 to 500 ohms per
square. In other embodiments, the sheet resistance of the conductive
micropattern falls within the range of 5 to 100 ohms per square. In other
embodiments, the sheet resistance of the conductive micropattern falls
within the range of 5 to 40 ohms per square. In other embodiments, the
sheet resistance of the conductive micropattern falls within the range of
10 to 30 ohms per square. In prescribing the sheet resistance that may
characterize a conductive micropattern or a region of a conductive
micropattern, the micropattern or region of micropattern is said to have
a sheet resistance of a given value if it has that sheet resistance value
for electrical conduction in any direction.

[0073] Appropriate micropatterns of conductor for achieving transparency
of the sensor and viewability of a display through the sensor have
certain attributes. First of all, regions of the conductive micropattern
through which the display is to be viewed should have an area fraction of
the sensor that is shadowed by the conductor of less than 50%, or less
than 25%, or less than 20%, or less than 10%, or less than 5%, or less
than 4%, or less than 3%, or less than 2%, or less than 1%, or in a range
from 0.25 to 0.75%, or less than 0.5%.

[0074] The open area fraction (or open area or Percentage of Open Area) of
a conductive micropattern, or region of a conductive micropattern, is the
proportion of the micropattern area or region area that is not shadowed
by the conductor. The open area is equal to one minus the area fraction
that is shadowed by the conductor, and may be expressed conveniently, and
interchangeably, as a decimal or a percentage. Area fraction that is
shadowed by conductor is used interchangeably with the density of lines
for a micropatterned conductor. Micropatterned conductor is used
interchangeably with electrically conductive micropattern and conductive
micropattern. Thus, for the values given in the above paragraph for the
fraction shadowed by conductor, the open area values are greater than
50%, greater than 75%, greater than 80%, greater than 90%, greater than
95%, greater than 96%, greater than 97%, greater than 98%, greater than
99%, 99.25 to 99.75%, 99.8%, 99.85%, 99.9% and even 99.95. In some
embodiments, the open area of a region of the conductor micropattern
(e.g., a visible light transparent conductive region) is between 80% and
99.5%, in other embodiments between 90% and 99.5%, in other embodiments
between 95% and 99%, in other embodiments between 96% and 99.5%, in other
embodiments between 97% and 98%, and in other embodiments up to 99.95%.
With respect to the reproducible achievement of useful optical properties
(e.g. high transmission and invisibility of conductive pattern elements)
and electrical properties, using practical manufacturing methods,
preferred values of open area are between 90 and 99.5%, more preferably
between 95 and 99.5%, most preferably between 95 and 99.95%.

[0075] To minimize interference with the pixel pattern of the display and
to avoid viewability of the pattern elements (e.g., conductor lines) by
the naked eye of a user or viewer, the minimum dimension of the
conductive pattern elements (e.g., the width of a line or conductive
trace) should be less than or equal to approximately 50 micrometers, or
less than or equal to approximately 25 micrometers, or less than or equal
to approximately 10 micrometers, or less than or equal to approximately 5
micrometers, or less than or equal to approximately 4 micrometers, or
less than or equal to approximately 3 micrometers, or less than or equal
to approximately 2 micrometers, or less than or equal to approximately 1
micrometer, or less than or equal to approximately 0.5 micrometer.

[0076] In some embodiments, the minimum dimension of conductive pattern
elements is between 0.5 and 50 micrometers, in other embodiments between
0.5 and 25 micrometers, in other embodiments between 1 and 10
micrometers, in other embodiments between 1 and 5 micrometers, in other
embodiments between 1 and 4 micrometers, in other embodiments between 1
and 3 micrometers, in other embodiments between 0.5 and 3 micrometers,
and in other embodiments between 0.5 and 2 micrometers. With respect to
the reproducible achievement of useful optical properties (e.g. high
transmission and invisibility of conductive pattern elements with the
naked eye) and electrical properties, and in light of the constraint of
using practical manufacturing methods, preferred values of minimum
dimension of conductive pattern elements are between 0.5 and 5
micrometers, more preferably between 1 and 4 micrometers, and most
preferably between 1 and 3 micrometers.

[0077] In general, the deposited electrically conductive material reduces
the light transmission of the touch sensor, undesirably. Basically,
wherever there is electrically conductive material deposited, the display
is shadowed in terms of its viewability by a user. The degree of
attenuation caused by the conductor material is proportional to the area
fraction of the sensor or region of the sensor that is covered by
conductor, within the conductor micropattern.

[0078] In general, it is desirable for a transparent touch screen sensor
to exhibit a low value of haze. Haze refers to a property related to the
scattering of light as it passes through a medium, e.g. as measured by a
Haze-Gard instrument (Haze-Gard plus, BYK Gardner, Columbia, Md.). In
some embodiments, the touch screen sensor exhibits haze less than 10%, in
some embodiments less than 5%, in some embodiments less than 4%, in some
embodiments less than 3%, in some embodiments less than 2%. Embodiments
are disclosed which achieve a desirable combination of high transmission
(also referred to as visible light transmittance), low haze, and low
conductor trace visibility for regions including conductor micropatterns.
The conductor micropatterns are thus especially useful when used as part
of a sensing area or region of a touch screen sensor display, e.g. when
the micropattern overlays a viewable region of the display.

[0079] In some embodiments, in order to generate a visible light
transparent display sensor that has uniform light transmission across the
viewable display field, even if there is a non-uniform distribution of
sheet resistance, e.g. derived from a non-uniform mesh of conductive
material, the sensors include isolated conductor deposits added to the
conductor micropattern that serve to maintain the uniformity of light
transmittance across the pattern. Such isolated conductor deposits are
not connected to the drive device (e.g., electrical circuit or computer)
for the sensor and thus do not serve an electrical function. For
example., a metal conductor micropattern that includes a first region
with a mesh of square grid geometry of 3 micrometer line width and 200
micrometer pitch (3% of the area is shadowed by the metal, i.e., 97% open
area) and second region with a mesh of square grid geometry of 3
micrometer line width and 300 micrometer pitch (2% of the area is
shadowed by the metal, i.e., 98% open area) can be made optically uniform
in its average light transmission across the two regions by including
within each of the open cells of the 300 micrometer pitch grid region one
hundred evenly spaced 3 micrometer by 3 micrometer squares of metal
conductor in the pattern. The one hundred 3 micrometer by 3 micrometer
squares (900 square micrometers) shadow an additional 1 percent of the
area for each 300 micrometer by 300 micrometer cell (90000 square
micrometers), thus making the average light transmission of the second
region equal to that of the first region. Similar isolated metal features
can be added in regions of space between contiguous transparent
conductive regions, e.g. contiguous transparent conductive regions that
include micropatterned conductors in the form of two dimensional meshes
or networks, in order to maintain uniformity of light transmittance
across the sensor, including the transparent conductive regions and the
region of space between them. In addition to isolated squares of
conductor, other useful isolated deposits of conductor for tailoring
optical uniformity include circles and lines. The minimum dimension of
the electrically isolated deposits (e.g., the edge length of a square
feature, the diameter of a circular feature, or the width of a linear
feature) is less than 10 micrometers, less than 5 micrometers, less than
2 micrometers, or even less than 1 micrometer.

[0080] With respect to the reproducible achievement of useful optical
properties (e.g. high transmission and invisibility of conductive pattern
elements), using practical manufacturing methods, the minimum dimension
of the electrically isolated deposits is preferably between 0.5 and 10
micrometers, more preferably between 0.5 and 5 micrometers, even more
preferably between 0.5 and 4 micrometers, even more preferably between 1
and 4 micrometers, and most preferably between 1 and 3 micrometers. In
some embodiments, the arrangement of electrically isolated conductor
deposits is designed to lack periodicity. A lack of periodicity is
preferred for limiting unfavorable visible interactions with the periodic
pixel pattern of an underlying display. For an ensemble of electrically
isolated conductor deposits to lack periodicity, there need only be a
single disruption to the otherwise periodic placement of at least a
portion of the deposits, across a region having the deposits and lacking
micropattern elements that are connected to decoding or signal generation
and/or processing electronics. Such electrically isolated conductor
deposits are said to have an aperiodic arrangement, or are said to be an
aperiodic arrangement of electrically isolated conductor deposits. In
some embodiments, the electrically isolated conductor deposits are
designed to lack straight, parallel edges spaced closer than 10
micrometers apart, e.g. as would exist for opposing faces of a square
deposit with edge length of 5 micrometers. More preferably the isolated
conductor deposits are designed to lack straight, parallel edges spaced
closer than 5 micrometers apart, more preferably 4 micrometers apart,
even more preferably 3 micrometers apart, even more preferably 2
micrometers apart. Examples of electrically isolated conductor deposits
that lack straight, parallel edges are ellipses, circles, pentagons,
heptagons, and triangles. The absence within the design of electrically
isolated conductor deposits of straight, parallel edges serves to
minimize light-diffractive artifacts that could disrupt the viewability
of a display that integrates the sensor.

[0081] The impact of the conductor micropattern on optical uniformity can
be quantified. If the total area of the sensor, and hence the conductor
micropattern, that overlays a viewable region of the display is segmented
into an array of 1 millimeter by 1 millimeter regions, preferred sensors
include conductor micropatterns wherein none of the regions have a
shadowed area fraction that differs by greater than 75 percent from the
average for all of the regions. More preferably, none have a shadowed
area fraction that differs by greater than 50 percent. More preferably,
none have a shadowed area fraction that differs by greater than 25
percent. Even more preferably, none have a shadowed area fraction that
differs by greater than 10 percent. If the total area of the sensor, and
hence the conductor micropattern, that overlays a viewable region of the
display is segmented into an array of 5 millimeter by 5 millimeter
regions, preferred sensors include conductor micropatterns wherein none
of the regions have a shadowed area fraction that differs by greater than
50 percent from the average for all of the regions. Preferably, none have
a shadowed area fraction that differs by greater than 50 percent. More
preferably, none have a shadowed area fraction that differs by greater
than 25 percent. Even more preferably, none have a shadowed area fraction
that differs by greater than 10 percent.

[0082] The disclosure advantageously allows for the use of metals as the
conductive material in a transparent conductive sensor, as opposed to
transparent conducting oxides (TCO's), such as ITO. ITO has certain
drawbacks, such as corrosion-related degradation in certain
constructions, a tendency to crack when flexed, high attenuation of
transmitted light (due to reflection and absorption) when deposited as a
coating with sheet resistance below 100 to 1000 ohms per square, and
increasing cost due to the scarcity of indium. ITO is also difficult to
deposit with uniform and reproducible electrical properties, leading to
the need for more complex and expensive electronics that couple to the
conductive pattern to construct a touch screen sensor.

[0083] Examples of useful metals for forming the electrically conductive
micropattern include gold, silver, palladium, platinum, aluminum, copper,
nickel, tin, alloys, and combinations thereof. In some embodiments, the
conductor is a transparent conducting oxide. In some embodiments the
conductor is ITO. The conductor may have a thickness between 5 nanometers
and 5 micrometers, or between 10 nanometers and 500 nanometers, or
between 15 nanometers and 250 nanometers. In many embodiments, the
thickness of the conductor is less than one micrometer. A desired
thickness for the conductor can be calculated by starting with the
desired sheet resistance and considering the micropattern geometry (and
in turn its effect on the current-carrying cross-section in the plane)
and the bulk resistivity of the conductor, as is known in the art. For
complicated geometries of micropattern, there are computational methods
in the art, e.g. finite difference methods or finite element methods that
can be used to calculate sheet resistance, referred to herein as modeling
the properties of a micropattern. Sheet resistance can be measured using
a number of techniques, including four-point probe techniques and
non-contact eddy-current methods, as are known in the art.

[0085] Conductor patterns according to the invention can be generated by
any appropriate patterning method, e.g. methods that include
photolithography with etching or photolithography with plating (see,
e.g., U.S. Pat. No. 5,126,007; U.S. Pat. No. 5,492,611; U.S. Pat. No.
6,775,907). Additionally, the conductor patterns can be created utilizing
one of several other exemplary methods (each discussed in more detail
below): [0086] 1. Laser cured masking (curing of a mask layer on a
metal film, and then etching); [0087] 2. Inkjet printing (of masking
material or of seed material for subsequent metal plating); [0088] 3.
Gravure printing (of a seed material for subsequent metal plating);
[0089] 4. Micro-replication (form micro-grooves in a substrate, then fill
with conductive material or with a seed material for subsequent metal
plating); or, [0090] 5. Micro-contact printing (stamping or rotary
printing of self-assembled monolayer (SAM) patterns on a substrate's
surface).

[0091] Utilizing high volume, high resolution printing methods generally
allow for precision placement of the conductive elements, and also allows
for the (pseudo-random) variation of the microconductors at a scale
compatible with commercially available display pixels, to limit optical
anomalies (for example moire patterns) that might otherwise occur.

[0093] Laser cured masking can be used to create microconductors by
selectively curing a pattern with an ultraviolet laser. Such a process
typically works with either film- (for example, PET) or glass-based
substrates. An exemplary laser cured masking process may include the
following steps: [0094] 1. A substrate is plated with metal, (for
example, silver or copper is sputter coated onto glass or PET film);
[0095] 2. UV curable masking ink is coated uniformly onto the plated
substrate, (for example, spin coating, and dip coating); [0096] 3. A
laser cures a portion of the printed ink, to form microconductor
electrodes in the active area of the touch sensor, and may also cure
(wider) lines that interconnect electrodes to connector pads (beam width
of the laser may be reduced by a photo mask); [0097] 4. Uncured ink is
removed (washed off); and [0098] 5. Metal plated on the substrate is
removed by etching, except for the pattern under the masking ink.

[0099] Inkjet Printing and plating of seed ink can be used to create
microconductors by printing of the desired pattern using relatively wide
lines of seed ink (catalytic ink), followed by selective curing with a UV
laser, and similar to the laser cured masking process described above.
The substrate for this process may be either film- (for example, PET) or
glass.

[0100] FIG. 3a and FIG. 3b show such a process, whereby: [0101] 1. Seed
ink 66 is inkjet printed onto a substrate 67; [0102] 2. A laser 65 cures
a portion of the printed ink, to form microconductor electrodes 68 in
active area(s) of the touch sensor, and may also cure (wider) lines that
interconnect electrodes to connector pads (the beam width of the laser
may be reduced by a photo mask); [0103] 3. Uncured ink is removed (washed
off); and, [0104] 4. The cured pattern of seed ink is electroless plated,
(with a conductive metal). The inkjet printing process minimizes the
amount of ink used, so it should be considered where inks are expensive,
(for example, seed inks). If ink has relatively low cost, inkjet printing
can be replaced by another process (for example, spin coating or dip
coating) that coats the whole substrate uniformly. Ink material and
processing for the Inkjet printing and plating of seed ink process
described above are available from Conductive Inkjet Technology division
of Carclo Technical Plastics, Cambridge, UK.

[0105] Gravure printing requires that the image to be printed is "etched"
into a metal plate which rotates on a drum. As the drum turns, the etched
surface is filled with ink which then gets deposited on the surface of
the film being printed as the ink-filled etched plate and the film
contact each other. The process is diagramed in FIG. 4, which shows a
film substrate 76 being printed with ink lines 74 from ink bath 73.
Impression cylinder 70 is rolls against printing drum 75, which has
etches 72 that fill with ink from inkbath 73. Such a process could be
used to make stock material for later processing or could be used to make
specific X or Y components of a high volume sensor.

[0106] Seed inks (or catalytic inks) may be printed by any of the methods
described above. After printing and curing, the inks can be electroless
plated with metals such as copper, resulting in high conductivity. Seed
ink manufacturers include Conductive Inkjet Technology, a division of
Carclo, located in Cambridge, UK and QinetiQ Company in Farnborough,
England. Cabot Printable Electronics and Displays of Albuquerque, N. Mex.
make inkjet printable silver conductive inks.

[0107] Micro-replication is yet another process that can be used to form
microcondcutors. The diagram in FIG. 5 shows a cross sectional view of
filled, or partially filled, micro-replicated channels. The channels may
be filled with seed ink 81 and then plated (see metallization layer 80)
to make them conductive. Alternatively the channels could be filled with
an ink that by itself is conductive, eliminating the need for the plating
process. A third alternative is to coat the substrate with a metal, then
mask the portions of metal in the (bottom of) the grooves, then etch away
the unmasked metal, (see, for example, patent applications No. 61/076,731
("Method of Forming a Microstructure") and 61/076,736 ("Method of Forming
a Patterned Substrate.")) The actual shape of the channels can be altered
to optimize the cross sectional shape and size that provides the lowest
level of optical interference while still ensuring high conductivity and
high production yields.

[0108] Filled micro-replicated channels can provide a conductor with a
high aspect ratio cross section (relative to masked metal films). Thus
maximum conductivity may be achieved with minimum optical visibility,
(narrow cross section in the direction of viewing). A method of filling
micro-replicated channels and desirable shapes of channels with high
aspect ratio are described in co-assigned US patent application
US2007016081 (Gaides, et. al.).

[0109] FIG. 6 shows a cross-profile of a high aspect ratio touch-surface
having micro-replicated electrodes that are deeper than they are wide. In
one embodiment, a micro-replicated structure that has a ratio of depth to
width greater than 1:1 will yield better performance. Generally, the
thinner width of the micro-replicated structure will allow more of the
light exiting the display to pass through the touch sensor. Further,
deeper rather than wider channels will reduce the surface area that will
limit reflection of light entering the sensor from the first surface.
These advantages are gained while not losing capacitive signal. FIG. 6
shows a finger 85 capacitively coupling with a printed copper electrodes
87 of touch sensor 86 not only to the top surface but also to the sides
of the sensor.

[0110] Micro-contact printing is yet another process that can be used to
form microcondcutors. Micro-contact printing is the stamping or rotary
printing of self-assembled monolayer (SAM) patterns on substrate
surfaces. The approach exhibits several technologically important
features, including the ability to be carried out for very fine scale
patterns (e.g., feature size of one tenth of a micrometer) and with the
extension of the patterned monolayer to the patterning of metals,
ceramics, and polymers.

[0111] An exemplary micro-contact printing process is as follows: [0112]
1. A substrate is coated with metal, (for example, silver or copper is
sputter coated or plated onto glass or PET film); [0113] 2. A
self-assembled mono-layer mask is stamped onto the plated substrate; and,
[0114] 3. Metal coated on the substrate is removed by etching, except for
the pattern under the mask.

[0115] A micro-contact printing process is described in, for example, U.S.
Pat. No. 5,512,131 (Kumar) and in co-pending 3M patent application No.
61/032,273 ("Methods of Patterning a Conductor on a Substrate").
Micro-contact printing is generally substrate independent. For example,
substrates can be PET, glass, PEN, TAC, or opaque plastic. As is known in
the art, micro-contact printing can be combined with metal deposition
processes to yield an additive patterning process (for example, including
electroless plating).

[0116] FIG. 7a shows a matrix sensor for a small capacitive touch screen.
Two patterns (91 and 92) of electrodes, interconnects, and connector pads
are printed on a flexible substrate (for example, PET). The two patterns
are then assembled together to form two layers of electrodes on parallel
planes, with electrodes on the top plane orthogonal to conductors on the
lower plane as shown (see FIG. 7b). Sometimes, a shield (not shown) is
required below the lower electrode plane.

[0117] The patterns represented in FIG. 7 may be printed using one of the
methods described herein, and a single printing process step was used to
simultaneously print the <10 nm micro-conductors that form electrodes,
and the interconnects lines (typically >10 nm) that carry signals from
electrodes to connector pads, and also the connector pads themselves may
be formed in the same print process. For example, the microcontact
printing process was used to simultaneously print patterns of 3 nm
microconductors and 500 nm conductive traces 706 as described with
respect to FIG. 27. This particular embodiment yielded several
advantages: [0118] 1. Alignment of electrodes with interconnects is
automatic and very accurate; [0119] 2. Interconnects can be printed much
narrower and more closely spaced than with other interconnect printing
processes, (for example, silkscreen printing of conductive inks); and
[0120] 3. The thickness of interconnects (perpendicular to the plane of
the substrate) is much less than with prior interconnect printing
processes, (for example, silkscreen printing of conductive inks). Thick
interconnects cause gaps between laminated layers which are visible and
can undermine the seal between laminated layers.

[0121] FIG. 8 shows the micro-replicated and filled "stock" construction
material with parallel micro-conductors 95 on a substrate 96 surface. Web
orientation is vertical (97). The substrate may be PET, PEN, or
polycarbonate, and the micro-conductors may be deposited in
micro-replicated grooves as disclosed herein and/or in 3M patent
application Nos. 61/076,731 ("Method of Forming a Microstructure") and
61/076,736 ("Method of Forming a Patterned Substrate"). Spacing of
micro-conductors is, in one embodiment, preferably between 50 μm and
500 μm.

[0122] This stock material may be processed into touch sensor components
(for example, electrodes or shields) by interconnecting selected
micro-conductors with printed (for example, inkjetted, or silkscreened)
dielectrics that provide insulating cross-overs whereby post-printed (for
example, inkjetted or silkscreened) conductive inks (printed using the
methods described herein) can bridge over some micro-conductors and make
contact only with selected micro-conductors. Thus interconnects and
connector pads are made for a sensor as shown in FIG. 9, which shows an
inkjet-printed dielectric surface 1002 with through-holes 1000 through
the dielectric, and conductive traces 1001 also printed by inkjet. While
FIG. 8 and FIG. 9 show micro-conductors printed in the direction of the
substrate web, it is sometimes advantageous to print micro-conductors in
a direction perpendicular to the substrate web.

[0123] FIG. 10 shows a cross section of an example of a matrix touch
sensor constructed with two layers of the stock micro-replicated
micro-conductor material, and two layers of post-printed inkjet
conductive traces, separated. The topmost layer 1010 includes
micro-replicated micro-conductors; the next layer 1011 is a printed
dielectric; the next layer 1012 includes post-processed conductors; the
next layer 1013 is an adhesive; the next layer 1014 is a post-processed
conductor; the next layer 1015 is a printed dielectric, and the final
layer 1016 includes micro-replicated microconductors.

[0124] In some embodiments, transparent conductive regions with different
sheet resistance in at least one direction are created by including
selective breaks in conductive traces within an otherwise continuous and
uniform mesh. This approach of selective placement of breaks is
especially useful for generating articles including patterns of visible
transparent conductive regions where the optical transmittance across the
article is uniform. The starting mesh can be isotropic or anisotropic.
For example., an elongated rectangular transparent conductive bar having
a square micromesh can be made to exhibit periodic sheet resistance along
its long axis by creating a periodic series of breaks, the breaks being
in traces that have a vector component in the direction of the long axis
and the periodicity being in the direction of the long axis. This
periodicity in sheet resistance can be useful for decoding the position
of an object (e.g., a finger) near the rectangular bar. By selecting the
width, thickness, and area density of traces, together with the
population of breaks, one can design periodic variation in the resistance
per unit length along a transparent conductive element characterized by
peaks in resistance per unit length that are at least 2 times the minimum
in resistance per unit length, preferably at least 5 times their minimum,
more preferably at least 10 times there minimum.

[0125] In other embodiments that include selective breaks in an otherwise
continuous and uniform mesh, the breaks can be placed in order to create
approximately continuously varying sheet resistance in a given direction.
The continuously varying sheet resistance can be useful for amplifying
the non-linearity of electric field along a transparent conductive
element, beyond that which would be created only by the overall shape of
the element. E.g., as is known in the art, a transparent conductive
element with uniform sheet resistance, in the form of an elongated
isosceles triangle with an electrical potential applied to its base
relative to its apex, exhibits non-linear electric field from base to
apex due to the gradient in resistance per unit length along the field
direction (created by the narrowing width of the triangle). For touch
sensors based on interdigitated arrays of such triangular transparent
conductive elements, it would be advantageous for the non-linearity in
electric field to be even greater, leading to greater signal-to-noise
ratio for circuitry used to decode the position of an object (e.g., a
finger) near the array. By selecting the width, thickness, and area
density of traces, together with the population of breaks, one can design
sheet resistance per unit length along a transparent conductive element
that increases by a factor of at least 1.1 over a distance of 1
centimeter, or at least 1.2, or at least 1.5, or at least 2.

[0126] In some embodiments, two transparent conductive regions with
different sheet resistance in at least one direction are created by
including in each of the two regions a contiguous mesh with its own
design, each mesh not necessarily including selectively placed breaks.
Examples of two meshes with designs that lead to different values of
sheet resistance for current passing in a single direction, e.g. the x
direction in FIG. 2, include two meshes with the same thickness
(dimension in the z direction in FIG. 2) of the same conductive material
deposit but with different amounts with current-carrying cross-sectional
area (y-z plane in FIG. 2) per unit width in the y direction. One example
of such a pair of mesh regions are two square grid regions each
comprising conductive traces of width 2 micrometers but with different
pitch, e.g. 100 micrometers and 200 micrometers. Another example of such
a pair of mesh regions are two rectangular grid regions (non-square, with
100 micrometer pitch in the one direction and 200 micrometer pitch in the
orthogonal direction) each comprising conductive traces of width 2
micrometers but with different orientation, e.g. with the long axes of
the rectangular cells in the first regions oriented at 90 degrees with
respect to the rectangular cells in the second region.

[0127] In some embodiments, the sensors include an insulating visible
light transparent substrate layer that supports a pattern of conductor,
the pattern includes a visible light transparent micropattern region and
a region having a larger feature that is not transparent, wherein the
visible light transparent micropattern region and the larger feature
region include a patterned deposit of the same conductor (e.g., a metal)
at approximately the same thickness. The larger feature can take the form
of, e.g., a wide conductive trace that makes contact to a visible light
transparent conductive micropattern region or a pad for making contact
with an electronic decoding, signal generation, or signal processing
device. The width of useful larger features, in combination on the same
insulating layer with visible light transparent conductive micropattern
regions, is e.g. between 25 micrometers and 3 millimeters, between 25
micrometers and 1 millimeter, between 25 micrometers and 500 micrometers,
between 25 micrometers and 250 micrometers, or between 50 micrometers and
100 micrometers.

[0128] One illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 0.5
and 5 micrometers. The first region micropattern has a first sheet
resistance value in a first direction between 5 and 500 ohm per square,
is visible light transparent, and has between 95% and 99.5% open area.
The second region micropattern has a second sheet resistance value in the
first direction that is different than the first sheet resistance value.

[0129] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 95% and 99.5%
open area.

[0130] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 1 and
4 micrometers. The first region micropattern has a first sheet resistance
value in a first direction between 5 and 100 ohm per square, is visible
light transparent, and has between 96% and 99.5% open area. The second
region micropattern has a second sheet resistance value in the first
direction that is different than the first sheet resistance value.

[0131] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 0.5
and 5 micrometers. The first region micropattern has a first sheet
resistance value in a first direction between 5 and 500 ohm per square,
is visible light transparent, and has between 95% and 99.5% open area.
The second region micropattern has a second sheet resistance value in the
first direction that is different than the first sheet resistance value.
The micropattern also includes electrically isolated conductor deposits.
For all 1 millimeter by 1 millimeter square regions of the sensor that
lie in the visible light transparent sensing area, none of the regions
have a shadowed area fraction that differs by greater than 75 percent
from the average for all of the regions.

[0132] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 0.5
and 5 micrometers. The first region micropattern has a first sheet
resistance value in a first direction between 5 and 500 ohm per square,
is visible light transparent, and has between 95% and 99.5% open area.
The second region micropattern has a second sheet resistance value in the
first direction that is different than the first sheet resistance value.
The micropattern also includes electrically isolated conductor deposits.
For all 5 millimeter by 5 millimeter square regions of the sensor that
lie in the visible light transparent sensing area, none of the regions
have a shadowed area fraction that differs by greater than 50 percent
from the average for all of the regions.

[0133] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 1 and 4 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 96% and 99.5%
open area.

[0134] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 95% and 99.5%
open area. The micropattern also includes electrically isolated conductor
deposits. For all 1 millimeter by 1 millimeter square regions of the
sensor that lie in the visible light transparent sensing area, none of
the regions have a shadowed area fraction that differs by greater than
75% from the average for all of the regions.

[0135] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 95% and 99.5%
open area. The micropattern also includes electrically isolated conductor
deposits. For all 5 millimeter by 5 millimeter square regions of the
sensor that lie in the visible light transparent sensing area, none of
the regions have a shadowed area fraction that differs by greater than 50
percent from the average for all of the regions.

[0136] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes metallic linear electrically
conductive features having a width between 0.5 and 5 micrometers. The
first region micropattern is visible light transparent, and has between
95% and 99.5% open area. For all 1 millimeter by 1 millimeter square
regions of the first region micropattern, none of the square regions have
a shadowed area fraction that differs by greater than 75 percent from the
average for all of the square regions. In one embodiment the first region
micropattern also includes electrically isolated conductor deposits. In
one embodiment, the metallic linear electrically conductive features have
a thickness of less than 500 nanometers. In one embodiment, the first
region micropattern has a first sheet resistance value in a first
direction between 5 and 100 ohm per meter.

[0137] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes metallic linear electrically
conductive features having a width between 0.5 and 5 micrometers. The
first region micropattern is visible light transparent, and has between
95% and 99.5% open area. For all 5 millimeter by 5 millimeter square
regions of the first region micropattern, none of the square regions have
a shadowed area fraction that differs by greater than 50 percent from the
average for all of the square regions. In one embodiment, the metallic
linear electrically conductive features have a thickness of less than 500
nanometers. In one embodiment, the first region micropattern also
includes electrically isolated conductor deposits.

[0138] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has a first sheet resistance value in a first direction
between 5 and 100 ohm per square, is visible light transparent, and has
between 95% and 99.5% open area. The micropattern also includes
electrically isolated conductor deposits. For all 1 millimeter by 1
millimeter square regions of the sensor that lie in the visible light
transparent sensing area, none of the regions have a shadowed area
fraction that differs by greater than 75 percent from the average for all
of the regions.

[0139] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has a first sheet resistance value in a first direction
between 5 and 100 ohm per square, is visible light transparent, and has
between 95% and 99.5% open area. The micropattern also includes
electrically isolated conductor deposits. For all 5 millimeter by 5
millimeter square regions of the sensor that lie in the visible light
transparent sensing area, none of the regions have a shadowed area
fraction that differs by greater than 50 percent from the average for all
of the regions.

[0140] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 0.5
and 5 micrometers. The first region micropattern has a first sheet
resistance value in a first direction between 5 and 500 ohm per square,
is visible light transparent, and has between 95% and 99.5% open area.
The second region micropattern has a second sheet resistance value in the
first direction that is different than the first sheet resistance value.
The sensor also includes larger electrically conductive features disposed
on or in the visible light transparent substrate, the larger features
comprising a continuous conductor deposit of the same material and
thickness as included in the micropattern and measuring at least 25
micrometers in minimum dimension.

[0141] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 95% and 99.5%
open area. The sensor also includes larger electrically conductive
features disposed on or in the visible light transparent substrate, the
larger features comprising a continuous conductor deposit of the same
material and thickness as included in the micropattern and measuring at
least 25 micrometers in minimum dimension.

[0142] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area and a second region micropattern. The electrically conductive
micropattern includes metallic linear electrically conductive features
having a thickness of less than 500 nanometers and a width between 0.5
and 5 micrometers. The first region micropattern has a first sheet
resistance value in a first direction between 5 and 500 ohm per square,
is visible light transparent, and has between 95% and 99.5% open area.
The second region micropattern has a second sheet resistance value in the
first direction that is different than the first sheet resistance value.
The sensor also includes larger electrically conductive features disposed
on or in the visible light transparent substrate, the larger features
comprising a continuous conductor deposit of the same material and
thickness as included in the micropattern and measuring at least 500
micrometers in minimum dimension.

[0143] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The electrically conductive micropattern includes metallic linear
electrically conductive features having a thickness of less than 500
nanometers and a width between 0.5 and 5 micrometers. The first region
micropattern has an anisotropic first sheet resistance with a difference
in sheet resistance values for orthogonal directions of a factor of at
least 1.5, is visible light transparent, and has between 95% and 99.5%
open area. The sensor also includes larger electrically conductive
features disposed on or in the visible light transparent substrate, the
larger features comprising a continuous conductor deposit of the same
material and thickness as included in the micropattern and measuring at
least 500 micrometers in minimum dimension.

[0144] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes conductive traces with width
between 0.5 and 10 micrometers. The first region micropattern is visible
light transparent and has between 90% and 99.95% open area, preferably
between 95% and 99.95% open area, and more preferably between 97% and 98%
open area. For all 5 millimeter by 5 millimeter square regions of the
first region micropattern, none of the square regions have a shadowed
area fraction that differs by greater than 75%, preferably differs by
greater than 50%, more preferably differs by greater than 25%, and most
preferably differs by greater than 10% from the average for all the
square regions. In one embodiment, the first region micropattern includes
conductive traces with width between 0.5 and 5 micrometers, preferably
between 1 and 3 micrometers.

[0145] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes conductive traces with width
between 1 and 10 micrometers. The first region micropattern is visible
light transparent and has between 90% and 99.5% open area. The first
region micropattern includes selective breaks in conductive traces within
an otherwise continuous and uniform mesh.

[0146] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes conductive traces with width
of about [X+0.5] in units of micrometers and an open area fraction
between [95-X]% and 99.5%. wherein 0≦X≦4.5. In one
embodiment, the touch screen sensor within the first region micropattern
exhibits a haze value less than 10% and transmission greater than 75%. In
another embodiment the touch screen sensor within the first region
micropattern exhibits a haze value less than 5% and transmission greater
than 85%. In one embodiment, the first region micropattern includes
conductive traces with width of about [98.5-(2.5/3.5)]% and
[99.5-(X/3.5)]% wherein 0≦X≦3.5.

[0147] Another illustrative touch screen sensor includes a visible light
transparent substrate and an electrically conductive micropattern
disposed on or in the visible light transparent substrate. The
micropattern includes a first region micropattern within a touch sensing
area. The first region micropattern includes parallel conductive traces
spaced 4 mm apart with width of about 9.6 μm, yielding an open area
fraction of 99.75%. This embodiment of microreplicated electrodes
comprises parallel conductors with a width of about 4 μm, to 10 μm,
separated by a distance of 0.5 mm to about 5 mm center to center.
Conductors may be formed lengthwise to a web of PET substrate, so lengths
of conductors may be greater than 1 m. Groups of adjacent conductors may
be electrically interconnected to form electrodes of 1 mm to 12 mm total
width, for example, using the process described with respect to FIG. 8
and FIG. 9. Conductors of adjacent electrodes may be interconnected such
that electrodes are interleaved as disclosed in, for example, co-pending
US Patent Application Publication No. 20070074914.

EXAMPLES

[0148] The following describe exemplary touch screen sensor designs. They
can be fabricated using known photolithographic methods, e.g. as
described in U.S. Pat. No. 5,126,007 or U.S. Pat. No. 5,492,611. The
conductor can be deposited using physical vapor deposition methods, e.g.
sputtering or evaporation, as is known in the art. Unless otherwise
noted, the examples below include conductors patterned by a micro-contact
printing technique (see technique description above and also co-pending
U.S. Patent Application No. 61/032,273). Each conductive pattern
exemplified herein is useful as a transparent touch screen sensor, when
connected to decoding circuitry, as is known in the art (e.g., U.S. Pat.
No. 4,087,625; U.S. Pat. No. 5,386,219; U.S. Pat. No. 6,297,811; WO
2005/121940 A2).

Example 1

[0149] A micropattern of thin film gold according to the following
description is deposited onto a thin sheet of colorless glass
(approximately 1 millimeter in thickness). The micropattern 240 is
depicted in FIG. 11 and FIG. 12. The thickness or height of the gold
layer is about 100 nanometers. The micropattern 240 involves a series of
horizontal (x-axis) mesh bars 241 comprising horizontal narrow traces
242, the traces 242 measuring approximately 2 micrometers in width. Four
of these horizontal mesh traces 242 are in electrical communication with
a larger feature contact pad 260. The mesh bars measure approximately 6
millimeters in width. Accordingly, with thirteen evenly spaced traces 244
traversing a width (y-axis) of 6 millimeters and thirteen evenly spaced
traces 242 traversing a length (x-axis) of 6 millimeters, the pitch of
the square grid of traces is 500 micrometers. As depicted in FIG. 12,
certain traces have breaks 250, measuring approximately 25 micrometers
(exaggerated in the figures, for ease in locating). For a square grid
with 2 micrometers wide opaque traces on a 500 micrometer pitch, the fill
factor for opaque traces is 0.80%, thus leading to an open area of
99.20%. For the same square grid, except with a 25 micrometer break every
500 micrometers, the fill factor is 0.78%, thus leading to an open area
of 99.22%. Thus, the design includes 1 mm×6 mm regions with 99.22%
open area and 6 mm×6 mm regions with 99.20% open area. The average
visible transmittance of the glass article with mesh is approximately
0.92*0.992=91% (with the factor of 0.92 related to interfacial reflection
losses in light transmission in the non-conductor-deposited areas of the
pattern). Along the horizontal bar direction, there is a series of
complete grid regions connected together by four traces of gold. Assuming
an effective bulk resistivity of 5E-06 ohm-cm for sputtered thin film
gold, each 2 micrometer wide, 500 micrometer long segment of thin film
gold has a resistance of approximately 125 ohms. The regions with a
completed grid, for current passing in the direction of the bars, have an
effective sheet resistance of approximately 115 ohms per square. The four
traces connecting the regions with completed grids create approximately
62.5 ohms of resistance between the regions. The above described
arrangement of conductive trace elements leads to a spatially varying
resistance per unit length along the bar direction as plotted in FIG. 13.
FIG. 14 illustrates an equivalent circuit for the array of horizontal
mesh bars. The circuit has a series of plates connected by resistors.

Example 2

[0150] A micropattern of thin film gold according to the following
description is deposited onto a thin sheet of colorless glass
(approximately 1 millimeter in thickness). The micropattern 340 is
depicted in FIG. 15. The thickness of the gold is about 100 nanometers.
The micropattern 340 has transparent conductive regions in the form of a
series of interdigitated wedges or triangles. Each wedge is comprised of
a mesh made up of narrow metallic traces 342, 344, the traces 342, 344
(see FIG. 15a-FIG. 15c) measuring approximately 2 micrometers in width.
The mesh wedges measure approximately 1 centimeter in width at their base
and approximately six centimeters in length. The pitch of the square grid
of traces 342, 344 is 500 micrometers. Within selected regions of the
mesh (see FIG. 15a-FIG. 15b), within a wedge, breaks 350 measuring
approximately 25 micrometers in length are placed intentionally to affect
the local sheet resistance within the wedge, for current passing along
its long axis. As depicted in FIG. 15a and FIG. 15b, regions 15a and 15b
(the regions being separated by approximately 1 centimeter in FIG. 15),
breaks 350 are included in the mesh that increase the sheet resistance in
the direction of the long axis by a factor greater than 1.2. The overall
design also includes region 15c (as depicted in FIG. 15c), which is
electrically isolated and spaced apart from regions 15a and 15b, and
which has a mesh of with sheet resistance value less than those of
regions 15a and 15b. The mesh region 15c has an open area of 99.20%,
while the mesh regions 15a and 15b have open area fractions of 99.20% and
99.21% respectively. The overall design also includes regions 15d and 15e
(as depicted in FIG. 15d and FIG. 15e) with meshes of larger pitch than
regions 15a, 15b and 15c, but with the same width of traces, leading to
increased sheet resistance and visible transmittance.

[0151] FIG. 16 illustrates the effect of engineering the mesh properties
as described above on the gradient in resistance along a wedge, versus
the use of a standard ITO coating for the same shape of region. The
overall design also includes larger conductive features in the form of
conductive leads along the left and right sides of the pattern, the leads
being approximately 1 millimeter wide and patterned from thin film gold
with approximately 100 nanometers thickness.

Example 3

[0152] A transparent sensor element 400 for a touch screen sensor is
illustrated in FIG. 17. The sensor element 400 includes two patterned
conductor layers 410, 414, (e.g., an X axis layer and a Y axis layer) two
optically clear adhesive layers 412, 416, and a base plate 418, laminated
together and depicted as separated in FIG. 17 for clarity. Layers 410 and
414 include transparent conductive mesh bars where one layer is oriented
in the x axis direction and the other layer is orientated in the y axis
direction, with reference to FIG. 2. The base plate 418 is a sheet of
glass measuring 6 centimeter by 6 centimeters in area and 1 millimeter in
thickness. A suitable optically clear adhesive is Optically Clear
Laminating Adhesive 8141 from 3M Company, St. Paul, Minn. For each of the
X-layer and the Y-layer, a clear polymer film with a micropattern of
metal is used. A micropattern of thin film gold according to the
following description is deposited onto a thin sheet of PET. Suitable PET
substrates include ST504 PET from DuPont, Wilmington, Del., measuring
approximately 125 micrometers in thickness.

[0153] The micropattern 440 is depicted in FIG. 18 and FIG. 19. The
thickness of the gold is about 100 nanometers. The micropattern has
transparent conductive regions in the form of a series of parallel mesh
bars 442. In addition to mesh bars that are terminated with square pads
460 (approximately 2 millimeters by 2 millimeters in area, comprising
continuous conductor in the form of thin film gold with thickness
approximately 100 nanometers) for connection to an electronic device for
capacitive detection of finger touch to the base plate, there are mesh
bars 441 that are electrically isolated from the electronic device. The
isolated mesh bars 441 serve to maintain optical uniformity across the
sensor. Each bar is comprised of a mesh made up of narrow metallic traces
443, the traces 443 measuring approximately 5 micrometers in width. The
mesh bars each measure approximately 2 millimeters in width and 66
millimeters in length. Within each mesh bar are rectangular cells
measuring approximately 0.667 millimeters in width and 12 millimeters in
length. This mesh design serves to provide ties between long-axis traces
in each mesh bar, to maintain electrical continuity along the mesh bar,
in case of any open-circuit defects in the long axis traces. However, as
opposed to the use of a square mesh with 0.667 millimeter pitch having
such ties, the rectangular mesh of FIG. 18 and FIG. 19 trades off sheet
resistance along the mesh bar with optical transmittance more optimally.
More specifically, the mesh bar depicted in FIG. 18 and FIG. 19 and a 2
millimeter wide mesh bar comprising a square mesh with 0.667 millimeter
pitch would both have essentially the same sheet resistance along the
long axis of the mesh bar (approximately 50 ohms per square); however,
the square grid would occlude 1.5% of the area of the transparent
conductive region and the mesh depicted in FIG. 18 and FIG. 19 occludes
only 0.8% of the area of the transparent conductive region.

Example 4

[0154] A transparent sensor element for a touch screen sensor is
described. The sensor element includes two patterned conductor layers,
two optically clear adhesive layers, and a base plate as depicted in FIG.
17. The base plate is a sheet of glass measuring 6 centimeter by 6
centimeters in area and 1 millimeter in thickness, laminated together as
depicted in FIG. 17. A suitable optically clear adhesive is Optically
Clear Laminating Adhesive 8141 from 3M Company. For each of the X-layer
and the Y-layer, a clear polymer film with a micropattern of metal is
used. A micropattern of thin film gold according to the following
description is deposited onto a thin sheet of PET. Suitable PET
substrates include ST504 PET from DuPont, measuring approximately 125
micrometers in thickness.

[0155] The micropattern 540 is depicted in FIG. 20 and FIG. 21. The
thickness of the gold is 100 nanometers. The micropattern 540 has
transparent conductive regions in the form of a series of parallel mesh
bars 542. In addition to mesh bars 542 that are terminated with square
pads 560 for connection to an electronic device for capacitive detection
of finger touch to the base plate, there are straight line segments 541
that are electrically isolated from the electronic device. The straight
line segments 541 lie in regions between the mesh bars 542, with
essentially the same geometry as the mesh bars, except for approximately
25 micrometer breaks 550 as depicted in FIG. 13. The isolated line
segments 541 serve to maintain optical uniformity across the sensor. Each
bar 542 is comprised of a mesh made up of narrow metallic traces, the
traces measuring approximately 5 micrometers in width. The mesh bars 542
each measure approximately 2 millimeters in width and 66 millimeters in
length. Within each mesh bar 542 are rectangular cells measuring
approximately 0.667 millimeters in width and 12 millimeters in length.
The mesh 542 depicted in FIG. 12 and FIG. 13 occludes 0.8% of its area
within the transparent conductive region. The isolated line segments 541
depicted in FIG. 12 and FIG. 13 also occlude 0.8% of the area within the
region they occupy between the mesh bars 542.

Example 5

[0156] A transparent sensor element for a touch screen sensor is
described. The sensor element includes two patterned conductor layers,
two optically clear adhesive layers, and a base plate as depicted in FIG.
17. The base plate is a sheet of glass measuring 6 centimeter by 6
centimeters in area and 1 millimeter in thickness, laminated together as
depicted in FIG. 17. A suitable optically clear adhesive is Optically
Clear Laminating Adhesive 8141 from 3M Company. For each of the X-layer
and the Y-layer, a clear polymer film with a micropattern of metal is
used. A micropattern of thin film gold according to the following
description is deposited onto a thin sheet of PET. Suitable PET
substrates include ST504 PET from DuPont, measuring approximately 125
micrometers in thickness.

[0157] The micropattern 640 is depicted in FIG. 22 and FIG. 23. The
thickness of the gold is about 100 nanometers. The micropattern 640 has
transparent conductive regions in the form of a series of parallel mesh
bars 642. In addition to mesh bars 642 that are terminated with square
pads 660 for connection to an electronic device for capacitive detection
of finger touch to the base plate, there are straight line segments 641
that are electrically isolated from the electronic device. The straight
line segments 641 lie in regions between the mesh bars, with a similar
geometry to the line segments of the mesh bars. The electrically isolated
line segments 641 serve to maintain optical uniformity across the sensor.
Each bar 641, 642 is comprised of narrow metallic traces, the traces
measuring approximately 3 micrometers in width. The mesh bars 642 each
measure approximately 2 millimeters in width and 66 millimeters in
length. Within each mesh bar 642 comprising randomly shaped cells. The
mesh 642 depicted in FIG. 22 and FIG. 23 occludes less than 5 percent of
its area within the transparent conductive region. The isolated line
segments 641 depicted in FIG. 22 and FIG. 23 also occlude less than 5
percent of the area within the region they occupy between the mesh bars.

[0159] A polymer film substrate was provided, polyethyleneterephthalate
(PET) (ST504, E. I. DuPont de Nemours and Company, Wilmington, Del.). The
optical properties of the ST504 PET film were determined by Haze-Gard.
The haze and the transmission measured approximately 0.67% and 92.9%,
respectively.

[0160] Some substrate films were coated with gold and some were coated
with silver. The gold-coated substrates were prepared by thermal
evaporation (DV-502A, Denton Vacuum, Moorestown, N.J.). For gold-coated
substrates, the substrate surface was first coated with 20 angstroms of
chromium and then coated with 100 nanometers of gold. In the case of
silver-coated substrates, two different methods were used. Some
silver-coated substrates were prepared by both thermal evaporation
(DV-502A, Denton Vacuum, Moorestown, N.J.) and some were prepared by
sputtering (3M). The substrate surface was coated with 100 nanometers of
silver in all cases.

[0161] Stamp Fabrication

[0162] Two different master tools for molding elastomeric stamps were
generated by preparing patterns of photoresist (Shipley1818, Rohm and
Haas Company, Philadelphia, Pa.) on 10-centimeter diameter silicon wafers
using photolithography. The different master tools were based on two
different mesh shapes, herein referred to as "Hex" and "Square". Hex
refers to a pattern comprising a network of lines that define enclosed
areas having the shape of a regular hexagon. Square refers to a pattern
comprising a network of lines that define enclosed areas having the shape
of squares. An elastomeric stamp was molded against the master tool by
pouring uncured polydimethylsiloxane (PDMS, Sylgard® 184, Dow Corning,
Midland Mich.) over the tool to a thickness of approximately 3.0
millimeters. The uncured silicone in contact with the master was degassed
by exposing to a vacuum, and then cured for 2 hours at 70° C.
After peeling from the master tool, a PDMS stamp was provided with a
relief pattern comprising raised features approximately 1.8 micrometers
in height. For both hex mesh and square mesh stamps, the raised features
of were the lines defining the respective mesh geometry, as described
above.

Inking

[0163] The stamp was inked by contacting its back side (flat surface
without relief pattern) to a solution of octadecylthiol ("ODT" O0005, TCI
AMERICA, Wellesley Hills, Mass.) in ethanol for 20 hours. 10 mM of ODT
solution was used for the stamp with square mesh pattern, and 5 mM of ODT
solution was used for the stamp with hex mesh pattern.

Stamping

[0164] Metalized polymer film substrates were stamped with inked stamps as
described above. For stamping, the metalized film was contacted to the
stamp relief patterned-surface, which was face up, by first contacting an
edge of the film sample to the stamp surface and then rolling the film
into contact across the stamp, using a foam roller with diameter of
approximately 3.0 centimeters. The rolling step required less than 1
second to execute. After rolling step, the substrate was contacted with
the stamp for 10 seconds. Then, the substrate was peeled from the stamp,
a step that required less than 1 second.

Etching

[0165] After stamping, the metallized film substrate with printed pattern
was immersed into an etchant solution for selective etching and metal
patterning. For printed metalized film substrates bearing a gold thin
film, the etchant comprised 1 gram of thiourea (T8656, Sigma-Aldrich, St.
Louis, Mo.), 0.54 milliliter of concentrated hydrochloric acid
(HX0603-75, EMD Chemicals, Gibbstown, N.J.), 0.5 milliliter of hydrogen
peroxide (30%, 5240-05, Mallinckrodt Baker, Phillipsburg, N.J.), and 21
grams of deionized water. To pattern the gold thin film, the printed
metalized film substrate was immersed in the etch solution for 50
seconds. For printed metalized film substrates bearing a silver thin
film, the etchant comprised 0.45 grams of thiourea (T8656, Sigma-Aldrich,
St. Louis, Mo.), 1.64 grams of ferric nitrate (216828, Sigma-Aldrich, St.
Louis, Mo.), and 200 milliliter of deionized water. To pattern the silver
thin film, the printed metalized film substrate was immersed in the etch
solution for 3 minutes. After patterned etching of the gold, residual
chromium was etched using a solution of 2.5 grams of potassium
permanganate (PX1551-1, EMD Chemicals, Gibbstown, N.J.), 4 grams of
potassium hydroxide (484016, Sigma-Aldrich, St. Louis, Mo.), and 100
milliliters of deionized water.

Characterization

[0166] After selective etching and metal patterning, the metal patterns
were characterized using an optical microscope (Model ECLIPSE LV100D
equipped with a DS-Fil digital camera and NIS-Elements D software, Nikon,
Melville, N.Y.), scanning electron microscope (SEM, Model JSM-6400, JEOL
Ltd, Tokyo, Japan), and Haze-Gard (Haze-Gard plus, BYK Gardner, Columbia,
Md.). The microscopic techniques were used to determine the width of line
features in the metal pattern. Haze-Gard was used to determine the
transmission and the haze for the mesh-grid coated films. The HazeGard
measurements were done after laminating the patterned film on a glass
with an optical clear adhesive (3M Product). The visibility factor of
high, medium, and low was assigned to describe the degree of visibility
of line features in the metal pattern (human observation with unaided
eye).

Example 6

[0167] A hexagonal mesh grid pattern of thin film gold was fabricated and
characterized according to the procedures described above. The ink
solution comprised octadecylthiol dissolved in ethanol at a concentration
of 5 mM. The ink solution was contacted to the back side of the stamp for
20 hours. The stamping time was 10 seconds. FIG. 1 gives an SEM
photomicrograph recorded from the completed thin film gold micropattern.
The actual line width measured approximately 1.63 micrometers. The
percentage of open area was recalculated based on the measured line width
and the designed edge-to-edge width of 400 micrometers, which is 99.2%.
The optical properties of the gold Hex mesh grid coated film were
determined by Haze-Gard. The haze and the transmission measured
approximately 1.14% and 91.6%, respectively. High visibility was assigned
to this example because the gold Hex mesh pattern with a line width of
1.63 micrometers and an edge-to-edge width of 400 micrometers can be
easily seen.

Examples 7 to 15

[0168] Hexagonal mesh grid patterns of thin film gold were fabricated and
characterized according to the procedures described in Example 1. The
actual line width for each example was measured using SEM and listed in
Table 1. The percentage of open area was then recalculated based on the
actual line width and designed edge-to-edge width and listed in Table 1.
Table 1 also gives the haze value and the transmission value for each
example measured by Haze-Gard and the visibility factors assigned to each
example.

Example 16

[0169] A square mesh grid pattern of thin film gold was fabricated and
characterized according to the procedures described above. The ink
solution comprised octadecylthiol dissolved in ethanol at a concentration
of 10 mM. The ink solution was contacted to the back side of the stamp
for 20 hours. The stamping time was 10 seconds. The actual line width
measured approximately 4.73 micrometers using optical microscope. The
percentage of open area was recalculated based on the measured line width
and the designed pitch of 320 micrometers, which is 97.0%. The optical
properties of the gold Square mesh grid coated film were determined by
Haze-Gard. The haze and the transmission measured approximately 1.58% and
88.6%, respectively. High visibility was assigned to this example because
the gold Square mesh pattern with a line width of 4.73 micrometers and a
pitch of 320 micrometers can be easily seen.

Examples 17-23

[0170] Square mesh grid patterns of thin film gold were fabricated and
characterized according to the procedures described in Example 11. The
actual line width for each example was measured using optical microscope
and listed in Table 1. The percentage of open area was then recalculated
based on the actual line width and designed pitch and listed in Table 1.
Table 1 also gives the haze value and the transmission value for each
example measured by Haze-Gard and the visibility factors assigned to each
example.

Example 24

[0171] A hex mesh grid pattern of thin film silver was fabricated and
characterized according to the procedures described above. The
silver-coated substrates were prepared by sputtering. The ink solution
comprised octadecylthiol dissolved in ethanol at a concentration of 5 mM.
The ink solution was contacted to the back side of the stamp for 20
hours. The stamping time was 10 seconds. FIG. 2 gives an SEM
photomicrograph recorded from the completed thin film silver
micropattern. The actual line width measured approximately 2.43
micrometers. The percentage of open area was recalculated based on the
measured line width and the designed edge-to-edge width of 600
micrometers, which is 99.2%. The optical properties of the gold Hex mesh
grid coated film were determined by Haze-Gard. The haze and the
transmission measured approximately 1.19% and 91.8%, respectively. High
visibility was assigned to this example because the silver Hex mesh
pattern with a line width of 2.43 micrometers and an edge-to-edge width
of 600 micrometers can be easily seen.

Examples 25 to 32

[0172] Hex mesh grid patterns of thin film silver were fabricated and
characterized according to the procedures described in Example 19. The
actual line width for each example was measured using SEM and listed in
Table 1. The percentage of open area was then recalculated based on the
actual line width and designed edge-to-edge width and listed in Table 1.
Table 1 also gives the haze value and the transmission value for each
example measured by Haze-Gard and the visibility factors assigned to each
example.

Example 33

[0173] A Square mesh grid pattern of thin film silver was fabricated and
characterized according to the procedures described above. The
silver-coated substrates were prepared by thermal evaporation. The ink
solution comprised octadecylthiol dissolved in ethanol at a concentration
of 10 mM. The ink solution was contacted to the back side of the stamp
for 20 hours. The stamping time was 10 seconds. The actual line width
measured approximately 5.9 micrometers using optical microscope. The
percentage of open area was recalculated based on the measured line width
and the designed pitch of 320 micrometers, which is 96.3%. The optical
properties of the silver Square mesh grid coated film were determined by
Haze-Gard. The haze and the transmission measured approximately 1.77% and
88.9%, respectively. High visibility was assigned to this example because
the silver Square mesh pattern with a line width of 5.9 micrometers and a
pitch of 320 micrometers can be easily seen.

Examples 34-40

[0174] Square mesh grid patterns of thin film silver were fabricated and
characterized according to the procedures described in Example 28. The
actual line width for each example was measured using optical microscope
and listed in Table 1. The percentage of open area was then recalculated
based on the actual line width and designed pitch and listed in Table 1.
Table 1 also gives the haze value and the transmission value for each
example measured by Haze-Gard and the visibility factors assigned to each
example.

[0175] A transparent sensor element was fabricated and combined with a
touch sensor drive device as generally shown in FIGS. 27, 28 and 29 using
microcontact printing and etching as described in co-assigned U.S.
Provisional application 61/032,273. The device was then integrated with a
computer processing unit connected to a display to test the device. The
device was able to detect the positions of multiple single and or
simultaneous finger touches, which was evidenced graphically on the
display. This example used micro-contact printing and etching techniques
(see also co-pending U.S. Patent App. No. 61/032,273) to form the
micro-conductor pattern used in the touch sensor.

Formation of a Transparent Sensor Element

[0176] First Patterned Substrate

[0177] A first visible light substrate made of polyethylene terephthalate
(PET) having a thickness of 125 micrometers (μm) was vapor coated with
100 nm silver thin film using a thermal evaporative coater to yield a
first silver metalized film. The PET was commercially available as
product number ST504 from E.I. du Pont de Nemours, Wilmington, Del. The
silver was commercially available from Cerac Inc., Milwaukee, Wis. as
99.99% pure 3 mm shot.

[0178] A first poly(dimethylsiloxane) stamp, referred to as PDMS and
commercially available as product number Sylgard 184, Dow Chemical Co.,
Midland, Mich., having a thickness of 3 mm, was molded against a 10 cm
diameter silicon wafer (sometimes referred to in the industry as a
"master") that had previously been patterned using standard
photolithography techniques. The PDMS was cured on the silicon wafer at
65° C. for 2 hours. Thereafter, the PDMS was peeled away from the
wafer to yield a first stamp having two different low-density regions
with patterns of raised features, a first continuous hexagonal mesh
pattern and a second discontinuous hexagonal mesh pattern. That is, the
raised features define the edges of edge-sharing hexagons. A
discontinuous hexagon is one that contains selective breaks in a line
segment. The selective breaks had a length less than 10 μm. The breaks
were designed and estimated to be approximately 5 μm. In order to
reduce their visibility, it found that, preferably, the breaks should be
less than 10 μm, more preferably, 5 μm or less, e.g., between 1 and
5 μm. Each raised hexagon outline pattern had a height of 2 μm, had
1% to 3% area coverage, corresponding to 97% to 99% open area, and line
segments that measured from 2 to 3 μm in width. The first stamp also
included raised features defining 500 μm wide traces. The first stamp
has a first structured side that has the hexagonal mesh pattern regions
and the traces and an opposing second substantially flat side.

[0179] The stamp was placed, structured side up, in a glass Petri dish
containing 2 mm diameter glass beads. Thus, the second, substantially
flat side was in direct contact with the glass beads. The beads served to
lift the stamp away from the base of the dish, allowing the following ink
solution to contact essentially all of the flat side of the stamp. A 10
millimolar ink solution of 1-octadecanethiol (product number C18H3CS,
97%, commercially available from TCI America, Portland Oreg.) in ethanol
was pipetted into the Petri dish beneath the stamp. The ink solution was
in direct contact with the second substantially flat side of the stamp.
After sufficient inking time (e.g., 3 hours) where the ink has diffused
into the stamp, the first stamp was removed from the petri dish. The
inked stamp was placed, structured side up, onto a working surface. The
first silver metalized film was applied using a hand-held roller onto the
now inked structured surface of the stamp such that the silver film was
in direct contact with the structured surface. The metalized film
remained on the inked stamp for 15 seconds. Then the first metalized film
was removed from the inked stamp. The removed film was placed for three
minutes into a silver etchant solution, which contained (i) 0.030 molar
thiourea (product number T8656, Sigma-Aldrich, St. Louis, Mo.) and (ii)
0.020 molar ferric nitrate (product number 216828, Sigma-Aldrich) in
deionized water. After the etching step, the resulting first substrate
was rinsed with deionized water and dried with nitrogen gas to yield a
first patterned surface. Where the inked stamp made contact with the
silver of the first metalized substrate, the silver remained after
etching. Thus silver was removed from the locations where contact was not
made between the inked stamp and silver film.

[0180] FIGS. 27, 27a and 27b show a first patterned substrate 700 having a
plurality of first continuous regions 702 alternating between a plurality
of first discontinuous regions 704 on a first side of the substrate,
which is the side that contained the now etched and patterned silver
metalized film. The substrate has an opposing second side that is
substantially bare PET film. Each of the first regions 702 has a
corresponding 500 μm wide conductive trace 706 disposed at one end.
FIG. 27a shows an exploded view of the first region 702 having a
plurality of continuous lines forming a hexagonal mesh structure.

[0181]FIG. 27b shows an exploded view of the first discontinuous region
704 having a plurality of discontinuous lines (shown as selective breaks
in each hexagon) forming a discontinuous hexagonal mesh structure. Each
mesh structure of regions 702 and 704 had 97% to 99% open area. Each line
segment measured from 2 to 3 μm.

[0182] Second Patterned Substrate

[0183] The second patterned substrate was made as the first patterned
substrate using a second visible light substrate to produce a second
silver metalized film. A second stamp was produced having a second
continuous hexagonal mesh pattern interposed between a second
discontinuous hexagonal mesh pattern.

[0184] FIGS. 28, 28a and 28b show a second patterned substrate 720 having
a plurality of second continuous regions 722 alternating between a
plurality of second discontinuous regions 724 on a first side of the
second substrate. Each of the second regions 722 has a corresponding 500
μm wide second conductive trace 726 disposed at one end. FIG. 28a
shows an exploded view of one second region 722 having a plurality of
continuous lines forming a hexagonal mesh structure. FIG. 28b shows an
exploded view of one second discontinuous region 724 having a plurality
of discontinuous lines (shown as selective breaks in each hexagon)
forming discontinuous hexagonal mesh structure. The selective breaks had
a length less than 10 μm. The breaks were designed and estimated to be
approximately 5 μm. In order to reduce their visibility, it found
that, preferably, the breaks should be less than 10 μm, more
preferably, 5 μm or less, e.g., between 1 and 5 μm. Each mesh
structure of region 722 and 724 had 97% to 99% open area. Each line
segment measured from 2 to 3 μm.

Formation of a Projected Capactive Touch Screen Sensor Element

[0185] The first and second patterned substrates made above were used to
produce a two-layer projected capacitive touch screen transparent sensor
element as follows.

[0186] The first and second patterned substrates were adhered together
using Optically Clear Laminating Adhesive 8141 from 3M Company, St. Paul,
Minn. to yield a multilayer construction. A handheld roller was used to
laminate the two patterned substrates with the regions of the first and
second conductive trace regions 706 and 726 being adhesive free. The
multilayer construction was laminated to a 0.7 mm thick float glass using
Optically Clear Laminating Adhesive 8141 such that the first side of the
first substrate was proximate to the float glass. The adhesive free first
and second conductive trace regions 706 and 726 allowed electrical
connection to be made to the first and second patterned substrates 700
and 720.

[0187] FIG. 29 shows a top plan view of a multilayer touch screen sensor
element 740 where the first and second patterned substrate have been
laminated. Region 730 represented the overlap of the first and second
continuous regions. Region 732 represented the overlap of the first
continuous region and the second discontinuous region. Region 734
represented the overlap of the second continuous region and the first
discontinuous region. And, region 736 represented the overlap between the
first and second discontinuous regions. While there was a plurality of
these overlap regions, for ease of illustration, only one region of each
has been depicted in the figure.

[0188] The integrated circuits used to make mutual capacitance
measurements of the transparent sensor element were PIC18F87J10
(Microchip Technology, Chandler, Ariz.), AD7142 (Analog Devices, Norwood,
Mass.), and MM74HC154WM (Fairchild Semiconductor, South Portland, Me.).
The PIC18F87J10 was the microcontroller for the system. It controlled the
selection of sensor bars which MM74HC154WM drives. It also configured the
AD7142 to make the appropriate measurements. Use of the system included
setting a number of calibration values, as is known in the art. These
calibration values can vary from touch screen to touch screen. The system
could drive 16 different bars and the AD7142 can measure 12 different
bars. The configuration of the AD7142 included selection of the number of
channels to convert, how accurately or quickly to take measurements, if
an offset in capacitance should be applied, and the connections for the
analog to digital converter. The measurement from the AD7142 was a 16 bit
value representing the capacitance of the cross point between conductive
bars in the matrix of the transparent sensor element.

[0189] After the AD7142 completed its measurements it signaled the
microcontroller, via an interrupt, to tell it to collect the data. The
microcontroller then collected the data over the SPI port. After the data
was received, the microcontroller incremented the MM74HC154WM to the next
drive line and cleared the interrupt in the AD7142 signaling it to take
the next set of data. While the sampling from above was constantly
running, the microcontroller was also sending the data to a computer with
monitor via a serial interface. This serial interface allowed a simple
computer program, as are known to those of skill in the art, to render
the raw data from the AD7142 and see how the values were changing between
a touch and no touch. The computer program rendered different color
across the display, depending on the value of the 16 bit value. When the
16 bit value was below a certain value, based on the calibration, the
display region was rendered white. Above that threshold, based on the
calibration, the display region was rendered green. The data were sent
asynchronously in the format of a 4 byte header (0xAAAAAAAA), one byte
channel (0x00-0x0F), 24 bytes of data (represents the capacitive
measurements), and carriage return (0x0D).

Results of Testing of the System

[0190] The transparent sensor element was connected to the touch sensor
drive device. When a finger touch was made to the glass surface, the
computer monitor rendered the position of touch that was occurring within
the touch sensing region in the form of a color change (white to green)
in the corresponding location of the monitor. When two finger touches
were made simultaneously to the glass surface, the computer monitor
rendered the positions of touches that were occurring within the touch
sensing region in the form of a color change (white to green) in the
corresponding locations of the monitor. When three finger touches were
made simultaneously to the glass surface, the computer monitor rendered
the positions of touches that were occurring within the touch sensing
region in the form of a color change (white to green) in the
corresponding locations of the monitor.

Example 42

[0191] One embodiment of microreplicated electrodes comprises parallel
conductors with a width of about 0.5 to about 5 microns (Y dimension in
FIG. 5), separated by a distance of about 2 mm to about 5 mm center to
center. Groups of adjacent conductors may be electrically interconnected
to form electrodes of 1 mm to 10 mm total width, for example, using the
process described with respect to FIG. 8 and FIG. 9.

[0192] The traces were made by forming rectangular microreplicated grooves
10 μm wide (X dimension in FIG. 5), 20 μm deep (Z dimension in FIG.
5), spaced 4 mm apart on a transparent substrate of PET using methods
described herein and by reference. The parallel array of grooves was 100
mm wide. Grooves were printed in the PET web direction so their length
was the length of the web, (>20 meters).

[0193] Grooves were filled with a seed ink manufactured by Conductive
Inkjet Technologies, (CIT). A thin layer of ink was smoothed over the
grooves then excess was removed with a doctor blade in a process similar
to silk screening. The seed ink was then cured using UV light. The
substrate with ink-filled grooves was then electroless plated with
copper. The resulting microconductors were each approximately 9.6 μm
wide. The ink filling, UV curing, and electroless plating process was
performed by CIT. Microconductors with substrates with grooves<10
μm wide, 20 μm deep, spaced 2 mm were also made using the process
described.

[0194] One skilled in the art will appreciate that the present invention
can be practiced with embodiments other than those disclosed. The
disclosed embodiments are presented for purposes of illustration and not
limitation, and the present invention is limited only by the claims that
follow.